Question

antarctica: not what you think
when people think of antarctica, they think of snow and ice. when they think of deserts, they think of sun, heat, and sand. yet in spite of its cold temperatures, antarctica is actually a desert. in fact, it is the largest desert on the planet. a desert is a very dry environment that receives less than ten inches of precipitation yearly. on average, antarctica gets less than two inches. most of that precipitation is in the form of snow, but rain or ice can sometimes fall as well.
what is the main, or central, idea of the passage?
most precipitation in antarctica is in the form of snow, though it can also get rain or ice.
even though antarctica is cold and has snow, it is a desert.

Explanation:

The passage starts by presenting common views of Antarctica (snow and ice) and deserts (sun, heat, sand). Then it uses "Yet" to introduce the key point: despite its cold, Antarctica is a desert. It further explains the desert definition (low precipitation) and Antarctica's precipitation details. The second option directly captures this main idea. The first option only focuses on precipitation form, which is a supporting detail, not the central idea.

Answer:

Even though Antarctica is cold and has snow, it is a desert.